Shuttle for sewing machines



NOV. 18, 1941. F, B- KEA| SHUTTLE FOR SEWING MACHINES Filed Oct. '19,1939 W' JJ Patented Nov. 18, 1941 SHUTTLE FOR SEWING MACHINES FrankBycroft Keall, Leicester, England, assigner to United Shoe MachineryCorporation, Borough of Flemington,` N. J., a corporation of New JerseyApplication October 19, 1939, Serial No. 300,220 In Great BritainOctober 24, 1938 (Cl. 112--232l 8 Claims.

This invention is concerned with improvements in or relating to shuttledevices for sewing machines and is particularly, but by no meansexclusively, concerned with oscillating shuttle devices for curved'hooked needle sewing machines of the well-known type used for bootor'shoe outsole stitching and for sewing suitcases or bags, asdisclosed, for instance in the patents to French and Meyer No. 473,870dated April 26, 1892,V and Ricks and Reid No. 1,695,718 dated December18, 1928.

Shuttle devices for machines of this type usually comprise three parts,namely a discoidal shuttle body of a somewhat semi-,cylindrical shapehaving a loop-taking ybeak at one side thereof and having a hollowcylindrical housing therein, a cylindrical bobbin case which is adaptedto fit within said housing, and a bobbin which is adapted to t withinthe bobbin case and to be placed with the latter, asa unit, intosaidhousing. The bobbin case usually has a thread tension device extendingperipherally around a groove in its side wall and, consequently, saidside walls are usually of a relatively thick construction. This factseriously restricts the dif ameter of bobbin which can be accommodatedin the case and, therefore, correspondingly restricts the amount ofthread which can be contained on the bobbin. This necessitates frequentreplenishment of fresh bobbins in the shuttle device.

With a view to allowing a bobbin housing of given diameter toaccommodate a bobbin. of greater diameter than is possible with thearrangement above referred to, there is described in the patent toMinett No. 1,883,812, dated October 18, 1932, an arrangement in which nobobbin case of usual type is used within the housing, there being aspindle in the housing for supporting the bobbin, a thin metal coverdetachably secured in the open end of the housing to retain the bobbintherein, and a thread tension device mounted on the interior of. the endface of the cover.

While such an arrangement as just referred to has proved to allow of theuse of bobbins containing a considerably greater quantity of thread thanthe bobbins housed in shuttle arrangements of the kind iirst abovereferred to, yet the arrangements described in the patent last mentionedsuffer from certain disadvantages. For example, not only has it proveddi'icult to provide effective and readily detachable means, able tostand up to long periods of wear, for securing the cover in place on theshuttle body, but the fact that the bobbin is mounted on a spindleprojecting from the shuttle body causes the bobbin to oscillate to andfro with the shuttle body and this, in turn, tends to cause thread to bedrawn off the bobbin in an undesirable manner and become ravelled withinthe shuttle housing.

Amongvthe several objects of the presentin- .venti'on are to provide aVshuttle arrangement which will combine the advantages arising from theuse of a thinV cover for the `shuttle housing with the benefit(yexistingliniknown shuttle arrangements) of holding the bobbin againstrotary movement with the shuttle body and, at thersame time, to overcomecertain disadvantages which are known to exist in the usual shuttlearrangement; e. g., that friction between ,the side wall of thebobbin-case housing in the shuttle body and the bobbin case tends tocause considerable wear to take place between thebobbin case and thelatching means which holds it against rotary movement with the shuttlebody.'

With the above in mind, a particular illustrative embodiment,hereinafter more fully described, of the present invention includes abobbinr or locking thread case in the form of athin shell having ontheinterior of its end face an adjustable thread tension spring of thecanti-v lever vtype, much like that described in thepatent to Minettiandhaving projecting axially of the thread case a hollow sleeve on which abobbin of large capacity is supported. The bobbin case, with the bobbinin it, is inserted into a housing in a shuttle body which has a pinprojecting axially of the housing to enter into the hollow sleeve on theshell-like bobbin case and thus support the latter, and the bobbin,centrally of the housing. The case also has a thread-exit noseprojecting radially from it and this nose is arranged to be engaged by alatch arm o f the usual type which, by its engagement with the nose,holds the thin bobbin case against .rotary movement with the shuttlebody. By reason of this fact the tendency previously experienced, whenmaking use of the arrangements described in the patent to Minett, forrotary to and fro movement of the bobbin case to cause ravelling of thethread therein is prevented. Moreover, by supporting the thin bobbincase on a pin projectingaxially of the housing for the latter and formedon the shuttle body, theundesired frictional'engagement which isexperienced in cases where a bobbin case is merely supported by the sidewall ,of the housing is obviated and thus the tendency for thebobbinvcase to rotate with the shuttle body is greatly reduced as isalso the consequent wear previously experienced between the nose on thecase and said latch arm. Thus the said illustrative embodiment, whilemaking it possible to use, in a shuttle housing of a given diameter, abobbin of greater capacity than has usually hitherto been possible, yetavoids the disadvantages which are likely to arise when making use ofshuttle-housing covers, such as are described in the patent to lVIinettwhich, together with the bobbin, partake of the rotary movement of theshuttle body.

In order that the various objects and the several features of thepresent invention (which features are set forth in the appended claims)may become clear, there will now be described with reference to theaccompanying drawing the illustrative embodiment aforementioned, fromwhich description, it will be gathered that the invention also includesvarious other novel details of construction and arrangement than thoseabove referred to.

In the drawing Figure 1 is a front-elevation of said illustrativeembodiment; Figure 2 is a rear elevation of the bobbin case of theillustrative embodiment; Figure 3 is a sectional view taken along theline II in Figure 1; Figure 4 is a detail view of part of the bobbincase taken in the direction of the arrow IV in Figure 1; Figure 5 is adetail View of part of the bobbin case taken in the direction of thearrow V in Figure 1; and Figure 6 is a detail sectional view taken alongthe line VI-VI in Figure 1.

The illustrative embodiment comprises a discoidal shuttle body I havinga loop taking beak 3 at one side and having formed therein a cylindricalhousing for a bobbin of thread 5 (Figure 3). A hollow pin 'I projectsaxially from the base of the housing and near its forward end a hardenedmetal plug 9 is inserted into the pin 1.

The plug 9 is seated against a neck formed in the interior of the hollowpin and can be pushed forwardly out of the pin, when it becomes badlyworn, to allow another similar plug to be inserted in its place.

For a purpose which will hereinafter become clear, the forward end faceof the plug 9 does not extend far enough forward to lie level with theforward end face of the pin 'I but, instead, the pin 'I extends beyondthe plug, and the forward end of the bore in it provides a small socketof 1f which the plug 9 provides the base.

The illustrative embodiment also includes a relatively thin shell-likebobbin case II, the thin peripheral wall I3 of which extends axially fora distance substantially equal to the width of the g The thin bobbin I5to be used in the shuttle I. case has provided on the interior of itsend face an adjustable thread-tension spring I'I generally similar tothat referred to as 39 in the patent to Minett, together with a fingerI9 (similar fit snugly over the hollow pin 'I projecting from theshuttle body I. It is contemplated that a full Ybobbin shall be insertedin the thin bobbin case and slid over the sleeve 2| and that the caseYtogether with the bobbin I5 in it, shall then be inserted in the housingin the shuttle body I with the sleeve 2| fitting over, and supported by,the hollow pin 'I of the latter. It will be understood that since thebobbin case has only a relatively thin peripheral wall I3, the bobbin I5may have a diameter but little less than that of the housing and that,since the bobbin case II is supported by the central pin I of theshuttle body I instead of resting against the side Wall of the housing,there will be very little frictional tendency for the bobbin case II orbobbin I5 to be carried round with the shuttle body I during the rotaryoscillating movements of the latter.

The central bobbin-supporting sleeve 2| on the bobbin case II'isrotatably mounted within the end wall of the bobbin case and carries, atthe interior of the oase, the finger I9. By rotating the sleeve 2| fromthe outer face of the bobbin case II (in a similar manner to thatdescribed in the Minett patent for rotating said finger 43) the finger|9- may be moved around the thread tension spring I'I to vary thetension applied to the thread by the spring I1. A hardened steel plug 23fitted into the sleeve 2| near its forward end is arranged to projectinto the socket at the forward end of the supporting pin 1 in theshuttle body and, by bearing against the Vhardened plug 9 in the pin 1,positions the relatively thin bobbin case I| endwise within .the housingand prevents chang of the end of its sleeve 2| against the base of thehousing. The plug 23 in the sleeve 2| abuts against a neck at theforward end ofthe sleeve and can be .driven out rearwardly to allow afresh plug to be inserted therein in case it should become worn.

Contrary, moreover, to the arrangement described in the Minett patent,it is intended that the thin bobbin case shallbe held against rotarymovement with the shuttle body and, for this purpose, it has projectingboth radially and forwardly from its forward face a thread-exit nose 25which is received in a groove in a bobbin-case retaining arm similar tothat disclosed in the patent to French and Meyer which both serves tohold the bobbin case more or less stationary during the rotary movementsof the shuttle body and holds it securely in place within the shuttlehousing. By this means ravelling of the thread in the bobbin lcase dueto angular movement of the latterY to and fro with the shuttle body isprevented.

The peripheral wall I3 of the relatively thin bobbin case I I has athread hole 21 formed in it about half way along itslength through whichthe thread t issues from the bobbin I5. From that hole, when threadingup the bobbin case, the thread t is led, externally of the case and in adirection parallel to its axis, to the adjacent end portion 29 of a slot3| which extends, for a purpose hereinafter described, from the junctionof the peripheral wall I3 and theY end wall of the bobbin case II aroundthe control sleeve 2| in the end wall of the bobbin case to the oppositeside of the nose 25, i. e., to the region indicated at 33 in Figure 1.From this region Va portion 35 ofthe slot 3| continues around theperipheral wall I3 of the bobbin case (see Figure 5) to a position justbelow the nose 25, as seen in Figure 5, where it leads into a threadexit hole 31 formed in the nose 25. The thread passes through the endportion 29 of the slot 3| into the interior of the case and immediatelypasses beneath the cantilever thread tension spring I'I, more or lessradially of the. case, between the spring and the end wall of the case.The thread ing sleeve 2|V in contact with about halfy the circumferenceof the latter and eventually passes out ofthe bobbin case through thethread'exit hole 3| in the nose 25 on the bobbin case, the threadissuing from the end of' the Vnose direct to the sewinginstrumentalities. Such a vpassage of the thread from the bobbin l5avoids,r as far as possible, the presence of sharp cornersaround whichthe thread must pass and this allows the degree of tension appliedto thethread by the cantilever spring to be controlled withinrelatively finelimits.

By reason of the precise arrangementjabove described, of theillustrative embodiment, it will be understood that the benefit inincreasing the thread holding capacity of the shuttle made possible bythe use of a relatively thin bobbin case with a thread tension device onits forward end is retained, that a very convenient means is used forholding the bobbin case in place and for preventing its rotation withthe shuttle body, that the central support for the case substantiallyeliminates the friction which has hitherto been responsible for thedevelopment of excessive wear between a bobbin case and its retaininglatch, that the renewable plugs 9 and 23 provide good bearing surfacesbetween the bobbin case and its supporting pin and prevent rapid weardeveloping between the end of the bobin case sleeve 2| and the base ofthe housing in the shuttle body, and that the combination of thecantilever` thread tension spring and the easy path in which the threadis led from the bobbin I5 enables a well controlled tension to beapplied to the thread.

The bobbin case has an external diameter substantially equal to theinternal diameter of the housing so that, especially at its inner openend, it ts closely within the housing. The thin wall of the bobbin caseis thus supported against distortion and injury by reason of the strainsexerted on the bobbin case during sewing by the thread tension deviceand restraining nose on the closed end wall of the bobbin case.

In placing a bobbin in its case the thread will rst be threaded throughthe hole 2'| from the inside of the case, after which the bobbin may beplaced in position on the sleeve 2| in the bobbin case The thread whichprotrudes from the hole 21 on the outside of the bobbin case is thenintroduced into the end portion 2S of the slot 3|, one side of the endportion 29 being formed by an upstanding lip 39 (see Figure 4) to enablethe thread more easily to slip into the slot. By pulling the threadaround the slot 3| until the end protrudes from the portion 35 of theslot 3|, the thread is caused to enter between the thread tension springand the end wall of the bobbin case l l, as indicated in Figures l and 2and the end of the thread is led through the hole 37 in the nose 25, itnally lying in the path shown in Figure 3.

As will be seen from Figure 1, the slot 3| in the end wall of the bobbincase is formed by two curved slots which are connected by a sharplycurved portion 4l, the inside edge 43 of which may be bent inwardlysomewhat, as indicated in Figure 6, (i. e., towards the base of thebobbin case housing) so as, in effect, to be shrouded by the outsideedge of the curved portion 4|. l This will insure that as a loop ofneedle thread is being passed over the bobbin case there will be no riskof the thread becoming trapped in the slot 3|, but

will be eased over the slot in the region of the portion-4|. Similarlyafter the loop of needle thread has been passed over the bobbin case the`upstanding lip 39 serves to guide the thread over the` end portion 29of vthe slot 3l.

The nature and scope of the invention having been indicated, and aspeci-c embodiment of the several features ofv the invention having beendescribed, what is claimed is:

p 1'.- In a sewing machine shuttle of the discoidal type, thecombinationof a shuttle body having a hollow cylindrical-housing, a cylindricalbobbin case Yhaving an external diameter substantially equal to the`internal diameter ofthe housing to nt within thehousing comprisingathin peripheral side wall `and an .end wall, a thread tension devicemountedv on the end wall inside of the bobbin case, guides to direct thebobbin thread to the tension device and from the tension device to thework, .and means on the'end wall outside of `the bobbin case' ,tocooperate with a latch arm to prevent rotationof the bobbin case withthe 'shuttle body. j A l 2. In a Isewing machine shuttle of thediscoidal type, the combination of a shuttle body having a hollowcylindrical housing, a cylindrical bob-bin case having an externaldiameter substantially equal to the internal diameter of the housing tot within the housing comprising a thin peripheral side wall and an endwall, a thread tension device mounted on the end wall inside of thebobbin case, a bobbin supporting sleeve projecting from the end wall, apin to form a journal for the sleeve projecting from the shuttl-e bodyaxially of the housing, guides to direct the bobbin thread to thetension device and from the tension device to the work, and means on theend wall outside of the bobbin case to cooperate with a latch arm toprevent rotation of the bobbin case with the shuttle body.

3. In a sewing machine shuttle of the discoidal typ, the combination ofa shuttle body having a hollow cylindrical housing, a cylindrical bobbincase to t within the housing comprising a peripheral side wall and anendwall, a bobbin supporting sleeve projecting from the end wall, a pin toform a journal for the sleeve projecting from the shuttle body axiallyof the housing, and renewable bearing plugs mounted at the end of thepin and on the end wall within the sleeve.

4. In a sewing machine shuttle of the discoidal type, the combination ofa shuttle body having a hollow cylindrical housing, a cylindrical bobbincase having an external diameter substantially equal to the internaldiameter of the housing to fit within the housing comprising aperipheral side wall and an end wall, a bobbin supporting sleeveprojecting from the end wall, a thread tension device mounted on the endwall inside of the bobbin case, guides to direct the bobbin thread tothe tension device and from the tension device to the work, and a quickthreading slot in the end wall of the thread case extendingsubstantially around the bobbin supporting sleeve for, directing thethread into engagement with the tension device.

5. In a sewing machine shuttle of the discoidal type, the combination ofa shuttle body having a hollow cylindrical housing, a cylindrical bobbincase to fit within the housing comprising a peripheral sidewall and anend wall, a bobbin supporting sleeve rotatably mounted in and projectingfrom the end wall, a thread tensioning spring mounted on the end wallinside of the bobbin case and extending around the sleeve,

and a tension adjusting lug on the 'sleeve ary ranged to bear againstthe spring.

6. In a sewing machine shuttle of the discoidal type, the combination ofa shuttle body having a hollow cylindrical housing, a cylindrical bobbincase having an external diameter substantially equal to the internaldiameter of the housing to fit Within the housing comprising a thin peripheral side wall and an end wall, a thread tension device mounted onthe end Wall inside of the bobbin case, a radially and axiallyprojecting nose on the end Wall outside of the bobbin case to cooperatewith a latch arm to prevent rotation of the bobbin case with the shuttlebody, and guides to direct the bobbin thread to the tension device andfrom the tension device through the nose to the Work.

7. In a sewing machine shuttle of the discoidal type, the combination ofa shuttle body having a hollow cylindrical housing, a cylindrical bobbincase having an external diameter substantially equal to the internaldiameter of the housing to t within the housing comprising a thinperipheral side Wall and an' end Wall, a thread tension device mountedon the end Wall inside of the bobbin case, a bobbin supporting sleeveprojecting from the end wall, a pin to form a journal for the sleeveprojecting from the shuttle body axially of the housing, a radially andaxially projecting nose on the end wall outside of the bobbin case tocooperate with a latch arm to prevent rotation of the bobbin case withthe shuttle body, and guides to direct the bobbin thread to the tensiondevice and from the tension device through the nose to the work.

8. In a sewing machine shuttle of the discoidal type, the combination ofa shuttle body having a hollow cylindrical housing, a cylindrical bobbincase to fit Within the housing comprising a peripheral side Wall and anend Wall, a bobbin supporting sleeve projecting from the end Wall, a pinto form a journal for the sleeve projecting from the shuttle bodyaxially of the housing, and an end thrust bearing within the sleevebetween the end of the pin and the end wall.

FRANK BYCROFT KEALL.

